The present disclosure relates to a motor for a washer, a method for controlling the motor, and a method for controlling the washer.
A motor is a device generating rotational motion of a rotor using external power.
A washer is for washing laundry. There are a variety of different types of washers, among which a drum type washer has a drum that is horizontally disposed and in which the laundry is loaded. A washer motor is mounted behind the drum to rotate the drum. A blushless direct current (BLDC) motor is mainly used as the washer motor that can rotate at a high speed and reduce noise.
The washer motor is designed to perform a flux weakening operation mode when a speed of the washer motor increases above a predetermined level so that the motor can rotate at a high speed even with relative small capacity and size.
In the flux weakening operation mode, an amount of the current applicable to the motor is reduced by counter electromotive force after the motor reaches a rated speed, so as to solve a limitation where the speed of the motor cannot increase even when the current is applied. That is, the flux weakening operation mode is a mode for forcedly weakening the magnetic flux. That is, the flux weakening operation mode is a mode for forcedly weakening the magnetic flux. In more detail, the flux weakening mode is a mode where, the flux is weakened by increasing an amount of the current applied in the d-axis that is in parallel with the magnetic flux direction of the permanent magnets in the d-q axis rotating coordinate system used in the vector control method after the motor reaches the rated speed. By this, the motor can be driven with a speed higher than the rated speed although the operating efficiency of the motor is deteriorated.
Meanwhile, the washer performs a variety of cycles, for example, such as a washing cycle for washing laundry loaded in a drum by rotating the drum, a rinsing cycle for rinsing the laundry that is washed, and a spinning cycle (dewatering cycle) for removing water from the laundry by rotating the drum at a high speed. The washer motor performs the flux weakening operation mode only considering a speed of the drum regardless of the above-described cycles.
However, the flux weakening operation mode may not be proper for some of the cycles.
When the flux weakening operation mode is performed and the drum reaches a predetermined speed or more, noise and vibration of the washer increase and sometimes the drum may break away.
In addition, the flux weakening operation mode may be forcedly performed due to a variety or causes (e.g., when the speed of the drum is inaccurately detected due to malfunction of a sensor). In this case, the operating efficiency of the motor is deteriorated and the washer malfunctions.